python - 根据组填充Nan

Question

我想根据列值的平均值填充 NaN。示例:

       Groups      Temp

1        5          27
2        5          23
3        5          NaN  (will be replaced by 25)
4        1          NaN  (will be replaced by the mean of the Temps that are in group 1)

有什么建议吗？谢谢!

Answer 1

将groupby、transfrom和lamdba函数与fillna和mean结合使用:

df = df.assign(Temp=df.groupby('Groups')['Temp'].transform(lambda x: x.fillna(x.mean())))
print(df)

输出:

   Temp
0  27.0
1  23.0
2  25.0
3   NaN